Tungsten-base alloy



Patented Mar. 2, 1937 UNITED STATES PATENT OFFICE TUNGSTEN-BASE ALLOY NoDrawing.

Original application January 2,

1935, Serial No. 105. Divided and this application September 26, 1936,Serial No. 102,818

3 Claims.

This application is divided out from my copending application Serial No.105 filed January 2, 1935, and relates to alloys for the points of goldnibs.

Many alloys for the purpose specified have already become known. Thereare tungsten-base alloys whose balance is made up by metals of theplatinum group. .There are other alloys with a base of platinum-groupsmetals, and up to 10% tungsten, with a small percentage of nickel or thelike. Lastly, there are alloys with iron, copper, or nickel as the base,with a small percentage of two metals of the platinum group, and oftungsten.

The many alloys of these types which have become known, are hard andsufficiently acid-proof, so that they do not wear rapidly, and are notattacked by ink. However, they are so brittle that it is difficult tosplit the nibs, and this operation 0 must be performed by means of avery thin and rapidly rotating disc of copper moistened with a paste ofemery. This is obviously an undesired complication which ought to beeliminated.

It is an object of my invention to provide an alloy for the points ofgold nibs which is as hard and acid-proof as the aforesaid known alloys,but at the same time possesses a high degree of tenacity so that nibshaving points of my novel alloy can be split simply by means of a bladeor shearing device.

To this end, I compound my novel alloy of tungsten as the base to whichis added a metal of the iron group, i. e., iron, nickel, or cobalt, asoft metal of the platinum group, i. e., platinum or palladium, andruthenium, which is a hard metal of the same group. The percentage ofplatinum or palladium should be higher than that of the hard metal.

I have found that the composition of an alloy which can be cut by theaforesaid cutting or shearing means, must fulfill certain conditions.The base of the alloy is tungsten, at the rate of to 80% of the alloy.However, up to 20% of the tungsten may be replaced by molybdenum, ortantalum, or by carbides of these metals. To this base I add metals ofthe iron group, i. e., iron, nickel, or cobalt, at the rate of 5 to 20%.Iron and nickel are less efllcient than cobalt, so that cobalt isnormally preferred.

The novel feature of my alloys is that their content of precious metalsconsists for the major part, preferably at the rate of 8 to 20%, of softmetals of the platinum group, i. e., platinum or palladium, and for theminor part, preferably at the rate of 2 to 10% of ruthenium. Rutheniumis particularly suitable as a constituent of my alloys, but rhodium andiridium may also be used.

My alloys may be prepared uniformly in any suitable manner, forinstance, in electric are or high frequency induction furnaces,preferably with inserted crucibles.

Heretofore, the soft metals of the platinum group, i. e., platinum andpalladium, were not added at comparatively high percentages, as thealloys for the points of nibs became too soft. However, I haveestablished the surprising fact that by adding platinum or palladium anda small percentage of ruthenium to a base of tungsten with iron, nickel,or cobalt, alloys are obtained whose hardness is equal to that of alloysconsisting principally of the said hard metals, but whose tenacity isvery much superior to that of the aforesaid alloys, and my novel alloyscan therefore be cut.

The tenacity of alloys is ascertained by placing a particle of the alloywhose diameter may be 1.3 millimeters, between a pair of jaws, andcompressing it until it is crushed. The crushing strength is determinedby the tenacity, and not by the hardness, of the alloy under test. Itamounts to only a few kilograms in brittle alloys, but may be 50kilograms, and more, for tenacious alloys.

As preferred examples of my preferred alloys, I give the following:

Example I.Tungsten 65%; cobalt 10%; platinum 20%; and ruthenium 5%.

Example II.-Tungsten 65%; palladium 15%; cobalt 10%; and ruthenium 10%.

Example III.-Tungsten 65%; platinum 15%;

cobalt 10%; and ruthenium 10%.

metal of the platinum group, platinum is preferred. My ruthenium alloysare second only to the osmium alloys in tenacity and areremarkablysuperior to known commercial alloys with respect to theircrushing strength.

My n'ovel alloys have the good property that they can be welded to goldnibs on account of their content of cobalt, while, as known, puretungsten and many alloys of tungsten, molybdenum, and metals of theplatinum group, cannot be welded directly to gold nibs.

I claim:

1. An alloy for points of gold nibs consisting of 65% of tungsten, 10%of cobalt, 20% of platinum, and 5% of ruthenium.

2. An alloy for points of gold nibs consisting of 80% of tungsten, 10%of cobalt, 8% of platinum, and 2% of ruthenium.

3. An alloy for points of gold nibs consisting of from 65% to 80% oftungsten, from 5% to 20% of a metal of the iron group, from 2% to 10% ofruthenium, and from 8% to 20% of platinum,

ALFRED JEDELE.

